The poet Charles Simic recalled in an essay his childhood in Belgrade, Yugoslavia, during World War II when he learned the lesson that the people who pay the highest price during war are the civilians. First, the Nazis bombed Belgrade. Then to drive the Nazis out, the Allies bombed Belgrade. He received an early education about the nature of war.

It is a lesson being relearned in Gaza. The conflict between Israel and Hamas, which controls Gaza, has devolved into a bitter, protracted fight that is taking a toll mainly on civilians. Day after day there is news about schools, shelters, hospitals that have been hit by Israeli bombardment. Day after day, despite the toll suffered by Gaza residents, Hamas sends rockets soaring over Israel.

The experience of civilians subjected to the punishment of war has been communicated to the outer world with immediacy and clarity because of the proliferation of social media where photos and footage provide abundant evidence of the terrible toll. It used to be that war photographers chronicled the carnage of war after the fact. Matthew Brady captured images of bodies on the fields of Antietam. In the following century photos and film footage brought the reality of World War II and Vietnam into the homes of America. In Vietnam, shock at what was happening, and the absence of an adequate justification, turned the public against the war. Absence of justification was key.

In recent conflicts, the U.S. military has sought to control media access to battlefields, embedding journalists with military units the better to control them. But now, everyone with an iPhone is a battlefield photographer, and there is no avoiding the truth of what is going on in Gaza and Israel.

Supporters of Israel argue that the vivid images of carnage in Gaza obscure a larger truth ó that Hamas precipitated this crisis and is making it worse by hiding its armaments in schools, hospitals and neighborhoods surrounded by civilians. These tactics put Israel at a disadvantage in the battle of electronic imagery and suggest the deeply cynical character of Hamas.

But Hamasí crimes obscure another larger truth ó that the occupation of Palestinian territories by Israel prolongs the unjust treatment of millions of ordinary Palestinian civilians. The failure of Israel and the Palestinian Authority to achieve a two-state solution has elevated the stature of Hamas, on the one hand, and, on the other, of those in Israel who want to hold onto the Palestinian territories forever.

And the civilians pay the price.

Public exposure to images of war often creates a backlash. Images showing the torture of Iraqis by Americans inside an Iraqi prison created public revulsion toward the Iraq war. Images of death and destruction in Gaza are turning public opinion in Europe against Israel. And yet Israel shows no sign of letting up in its campaign to destroy Hamasí capacity for attack.

Whatever geopolitical difficulties the imagery of war creates, public exposure to the harsh realities of war brings home the message that Charles Simic learned during World War II, and that is a good thing. Politicians need to be reminded of who suffers in a war, and the decision to wage war must always be a difficult one. Too often leaders far removed from the war zone are cavalier and hasty in their decisions. After all, it is the civilians who suffer, as they did in Iraq, as they did in Vietnam, as they did in Europe in World War II.

Sometimes wars must be fought despite the costs, and yet Israelís justifications in this case are being put to a harsh test. If Israel is right to defend itself, and it is, then it must also face up to the cost of defending itself, and its friends must be willing to stare at the harsh facts in the rubble of Gaza. And yet those facts continually challenge Israelís justifications, requiring further justification, and also demanding an unrelenting search for peace.